WO2017061469A1 - Identification system, identification device and identification method - Google Patents

Abstract

An identification device (10) receives detection information from a security device (20) which detects activity relating to an illegal intrusion into a network or an infection of a terminal (50), and identifies the state of the terminal (50) from the activity of the terminal (50) and terminal (50) information included in the detection information. If the state of a terminal (50) is identified by a state identification unit (11) as being a malware-infected state, the identification device (10) identifies, on the basis of connection information stored by a configuration information storage device (30), a terminal (50) suspected of having been infected up to the terminal (50) activity included in the detection information, and identifies, as an infected terminal candidate which might be infected, a terminal (50) positioned on a path the infected terminal might use in a future illegal intrusion or terminal infection.

Description

SPECIFIC SYSTEM, SPECIFIC DEVICE, AND SPECIFIC METHOD

The present invention relates to a specific system, a specific device, and a specific method.

Conventionally, the existence of malicious software such as malicious software and program code created with the intention of performing illegal and harmful operations such as computer viruses, spyware, and bots, known as malware, is known.

For example, there is Attack Graph as a technique for calculating propagation path candidates for such targeted attacks by malware and APT (Advanced Persistent Threat) attacks. Attack Graph is a technology that evaluates network threats by collecting network system configuration, terminal OS / application information, and statically calculating intrusion route candidates of external attackers.

Subil Abraham, Suku Nair, “A Predictive Framework for Cyber Security Analytics using Attack Graphs”, IJCNC 2015.

However, the conventional technology has a problem in that it is impossible to appropriately identify a terminal that is suspected of being infected or an infected terminal that may be infected in the future. For example, targeted attacks and APT attacks have the feature of expanding intrusion or infection to multiple terminals in the same network system via unauthorized intrusion or malware-infected terminals, which are detected by security devices Even if a countermeasure such as blocking is performed on the infected terminal, if there is another undetected infected terminal, the attack is continued through the terminal. In such a case, according to the conventional technology, it is impossible to appropriately identify a terminal that is suspected of being infected on the path to the detected terminal or an infected terminal that may be infected in the future.

In order to solve the above-described problems and achieve the object, a specification system of the present invention includes a configuration information storage device that stores information about a terminal in a network, and a specification device that specifies a state of the terminal. The configuration information storage device stores connection information indicating a connection relationship between terminals in the network, and the specific device detects security related to unauthorized intrusion into the network or terminal infection. The detection information is received from the device, the state specifying unit for specifying the state of the terminal from the information of the terminal included in the detection information and the activity content of the terminal, and the state of the terminal is infected with malware by the state specifying unit If it is identified as a state, the detection information is included in the detection information based on the connection information stored by the configuration information storage device. It is possible to identify a terminal that is suspected of being infected before reaching the contents of the terminal activity, and the infected terminal may infect a terminal located on a route that may be used for unauthorized intrusion or terminal infection in the future. It has the infection specific part to identify with the candidate of an infected terminal, It is characterized by the above-mentioned.

In addition, the specific device of the present invention receives detection information related to detection from a security device that detects activity related to unauthorized intrusion into a network including a plurality of terminals or infection of the terminals, and information on the terminals included in the detection information and When the state specifying unit that specifies the state of the terminal from the activity content of the terminal and the state specifying unit specifies that the state of the terminal is infected with malware, connection between terminals in the network Based on the connection information indicating the relationship, a terminal that is suspected of being infected before reaching the terminal activity content included in the detection information is identified, and the infected terminal may be used for unauthorized intrusion or terminal infection in the future. It is characterized by having an infection specifying unit for specifying a candidate for an infected terminal that may infect a terminal located on the route.

The identification method of the present invention is a identification method executed by the identification device, and receives detection information related to detection from a security device that detects activities related to unauthorized intrusion into a network including a plurality of terminals or terminal infection. Then, a state specifying step for specifying the state of the terminal from the information on the terminal included in the detection information and the activity content of the terminal, and the state specifying step is specified as a state in which the terminal is infected with malware. In such a case, based on the connection information indicating the connection relationship between the terminals in the network, the terminal that is suspected of being infected before reaching the activity content of the terminal included in the detection information is identified. Infection identification that identifies a candidate for an infected terminal that may infect a terminal located on a route that may be used for unauthorized intrusion or terminal infection Characterized in that it contains a degree.

According to the present invention, there is an effect that it is possible to appropriately identify a terminal that is suspected of being infected and a candidate for an infected terminal that may be infected in the future.

FIG. 1 is a diagram illustrating an example of a configuration of a specific system according to the first embodiment. FIG. 2 is a diagram illustrating an example of terminal connection information stored in the configuration information storage device according to the first embodiment. FIG. 3 is a diagram illustrating an example of terminal state information stored in the configuration information storage device according to the first embodiment. FIG. 4 is a diagram for explaining the process of specifying the state of the terminal in the specifying apparatus according to the first embodiment. FIG. 5 is a diagram for explaining a process for identifying a terminal suspected of being infected and a candidate for an infected terminal in the identifying apparatus according to the first embodiment. FIG. 6 is a diagram for explaining how to deal with a terminal whose infection is confirmed in the attack countermeasure apparatus according to the first embodiment. FIG. 7 is a diagram for explaining a process for identifying a terminal suspected of being infected and a candidate for an infected terminal in the identifying apparatus according to the first embodiment. FIG. 8 is a diagram for explaining how to deal with a terminal having a high possibility of infection in the attack countermeasure apparatus according to the first embodiment. FIG. 9 is a flowchart showing the flow of processing of the specific apparatus according to the first embodiment. FIG. 10 is a sequence diagram showing a flow of processing of the specific system according to the first embodiment. FIG. 11 is a diagram illustrating a computer that executes a specific program.

Hereinafter, embodiments of a specific system, a specific device, and a specific method according to the present application will be described in detail with reference to the drawings. In addition, the specific system, specific apparatus, and specific method which concern on this application are not limited by this embodiment.

[First embodiment]
In the following embodiments, the configuration of the specific system, the specific device, and the processing flow of the specific system according to the first embodiment will be described in order, and finally the effects of the first embodiment will be described.

[Specific system configuration]
FIG. 1 is a diagram illustrating an example of a configuration of a specific system according to the first embodiment. The identification system 1 according to the first embodiment includes a identification device 10 that identifies a terminal that is suspected of being infected or a terminal that may be infected in the future, a security device 20 that monitors communication, and a terminal 50A in the network. Configuration information storage device 30 for storing information about 50E, attack countermeasure device 40 for monitoring and restricting communication, a plurality of terminals 50A to 50E, NW (Network) equipment 60 such as a firewall, router, switch, network It has the mail server 70 which provides a service.

Further, the NW device 60 and the mail server 70 are connected to the Internet 80. Further, it is assumed that a network including a plurality of terminals 50A to 50E permits only communication necessary for business execution using a firewall ACL (Access Control List) or the like. In FIG. 1, communication permitted by the firewall and logical communication of service connectivity (email, HTTP proxy, authentication system, etc.) are shown as device connection arrows. In addition, the number of each apparatus and function shown in FIG. 1 is an example to the last, and is not restricted to this. In addition, when a plurality of terminals 50A to 50E are described without distinction, they are appropriately described as terminals 50.

The security device 20 monitors the communication of each of the terminals 50A to 50E and the NW device 60 in the network, and transmits detection information to the specific device 10 when detecting unauthorized communication or the like. The detection information includes information on the terminal 50 that performed unauthorized communication, activity contents of the terminal 50, and the like.

The configuration information storage device 30 stores connection information indicating a connection relationship between terminals in the network. For example, as illustrated in FIG. 2, the configuration information storage device 30 includes a “terminal name” indicating the name of the terminal, an “IP address” indicating the IP address of the terminal, and a “MAC address” indicating the MAC address of the terminal. The “connection information” indicating the connection relationship between the terminals is stored in association with each other.

2, the configuration information storage device 30 includes a terminal name “terminal 1”, an IP address “10.1.1.1”, and a MAC address “70: 58: 12: 27: B7: 17”. And the connection information “mail server → terminal 1, terminal 1 → terminal 3” are stored in association with each other. This is because the IP address of the terminal 1 is “10.1.1.1”, the MAC address is “70: 58: 12: 27: B7: 17”, and the mail server 70 and the terminal 3 are connected. It means that there is.

Further, the configuration information storage device 30 includes terminal status information indicating the status of the terminal 50 specified by the status specifying unit 11 described later, a terminal suspected of being infected specified by the infection specifying unit 12 described later, and the infected terminal. Memorize the candidates. For example, as illustrated in FIG. 3, the configuration information storage device 30 includes a “terminal name” indicating the name of the terminal, a “terminal status” indicating the terminal status, and a “suspicion of infection score” indicating the degree of suspected infection. And an “infection risk score” indicating the degree of risk of infection in association with each other.

Here, the terminal status includes “suspected infection”, “infection”, “non-infection”, “infection spread candidate”, and “attacked”. “Suspected infection” is a state in which there is a suspicion of infection. “Infection” is a state in which infection is confirmed. “Non-infectious” is an uninfected state. The “infection extension candidate” is a state in which there is a possibility of infection in the future. “Attacked” is a state of being attacked by an infected terminal or the like. It is assumed that the higher the value of the suspected infection score, the stronger the suspicion of infection, and the higher the value of the infection risk score, the higher the possibility of infection.

Referring to the example of FIG. 3, the configuration information storage device 30 sets the terminal name “terminal 1”, the terminal state “suspected infection”, the suspected infection score “0.33”, and the infection risk score “0.1”. Store in association with each other. This means that the current state of the terminal 1 is a suspected infection state, the suspected infection score is “0.33”, and the infection risk score is “0.1”.

Here, the terminal name “terminal 1” corresponds to the terminal 50A in FIG. 1, the terminal name “terminal 2” corresponds to the terminal 50B in FIG. 1, and the terminal name “terminal 3” 1 corresponds to the terminal 50C in FIG. 1, the terminal name “terminal 4” corresponds to the terminal 50D in FIG. 1, and the terminal name “terminal 5” corresponds to the terminal 50E in FIG. And

Further, the attack countermeasure device 40 applies to an infected terminal specified by the state specifying unit 11 described later and a terminal having a high suspicion of infection among terminals suspected of being infected specified by the infection specifying unit 12 described later. , Block communication, monitor communication or restrict communication.

The identifying device 10 identifies the state of the terminal, and identifies a terminal that is suspected of being infected and a terminal that is likely to be infected in the future. As illustrated in FIG. 1, the specifying device 10 includes a state specifying unit 11 and an infection specifying unit 12.

The state specifying unit 11 receives detection information from the security device 20 that detects an activity related to unauthorized intrusion into the network or infection of the terminal 50, and based on the information on the terminal 50 and the activity content of the terminal included in the detection information. The state of the terminal 50 is specified. For example, when the detection information is information related to communication, the state specifying unit 11 specifies the state of the terminal 50 corresponding to the transmission source address and the transmission destination address of the communication, and the detection information is information related to the terminal 50. In the case, the state of the terminal 50 is specified.

For example, the state specifying unit 11 detects that the detection information “terminal 4” communicates with “terminal 5” and “terminal 4” attacks “terminal 5”. In the case of the information to the effect, the state of “terminal 4” corresponding to the transmission source address and “terminal 5” corresponding to the transmission destination address is specified as information related to communication. In addition, for example, when the detection information is information indicating that “terminal 3” is infected with malware, the state specifying unit 11 specifies the state of “terminal 3” as information regarding the terminal 50. .

Here, the process of specifying the state of the terminal in the specifying device 10 will be described using the example of FIG. FIG. 4 is a diagram for explaining the process of specifying the state of the terminal in the specifying apparatus according to the first embodiment. In FIG. 4, the numbers next to the terminals 50A to 50E are numerical examples of infection suspect scores and infection risk scores of the terminals. In a state where there is no attack, the suspected infection numerical value is “0” in all the terminals 50. Further, the infection risk is set according to a certain rule in the terminal 50 having connectivity with the Internet 80. In the example of FIG. 4, “0.1” is added as a numerical value to a terminal that is directly connected to the Internet 80 and the infected terminal, but is not limited to this, and the numerical value is determined. The method can be set arbitrarily.

In the example of FIG. 4, the terminal 50C having the terminal name “terminal 3” is infected with malware, and C & C communication, which is communication performed with a server of an external network to control the infected terminal from the outside, is installed in the network. The processing when the security device 20 detects will be described. As illustrated in FIG. 4, the state specifying unit 11 of the specifying device 10 determines the terminal 50 </ b> C based on the information that the terminal 3 included in the detection information received from the security device 20 has performed C & C communication with the outside. The state of is identified. Here, when the state specifying unit 11 detects C & C communication of the terminal 3, it can be determined that the terminal 3 is infected with malware, so the state of the terminal 3 is specified as an infected state. The infection suspicion score is set to “1.0”.

If the state specifying unit 11 specifies that the state of the terminal 50 is infected with malware, the infection specifying unit 12 is included in the detection information based on the connection information stored by the configuration information storage device 30. The terminal 50 that is suspected of being infected before reaching the content of the activity of the terminal 50 to be identified is identified, and the infected terminal 50 can infect the terminal 50 that is located on a route that may be used for unauthorized intrusion or terminal infection in the future. To identify potential infected terminals.

For example, the infection identification unit 12 identifies the terminal 50 included in the communication path that can be the infection path of the infected terminal identified by the state identification unit 11 as the terminal 50 that is suspected of being infected, and the number of communication paths that can be the infection path. And a numerical value indicating the degree of suspicion of infection for each terminal 50 suspected of infection based on the past terminal state.

In addition, for example, the infection identification unit 12 may infect the terminal 50 that can be infected from the infected terminal using the connection information starting from the infected terminal identified by the state identification unit 11. Identified as a candidate.

Here, with reference to the example of FIG. 5, a description will be given of the process of identifying the terminal 50 that is suspected of being infected in the identifying apparatus 10 and the candidate for the infected terminal. FIG. 5 is a diagram for explaining a process for identifying a terminal suspected of being infected and a candidate for an infected terminal in the identifying apparatus according to the first embodiment. In the example of FIG. 5, it is assumed that the state identification unit 11 identifies the state of “terminal 3” as an infection state and the infection suspicion score is “1.0”.

The infection identification unit 12 of the identification device 10 first identifies the infection route of the terminal 3 using the connection information of the configuration information storage device 30 when the state of the “terminal 3” included in the detection information is identified. . In the example of FIG. 5, as infection route candidates to the terminal 3, there are a total of three routes: an attack directly performed from the Internet 80 via the NW device 60, an attack via the terminal 1, or an attack via the terminal 2. Conceivable.

Therefore, the infection suspect score to be added from the number “3” of communication routes that can be infection routes is set to “0.33 (1/3)” and added to the past infection suspect scores of the terminal 1 and the terminal 2 to The infection suspicion score, which is a numerical value indicating the degree of suspicion, is calculated. In addition, regarding the allocation of infection suspicion scores when there are multiple infection routes, we explained the case of evenly allocating in units of routes, but weighted allocation using statistical information is also possible, and the numerical value determination method Is not limited to this.

Next, the infection identification unit 12 identifies a candidate for the next infection spread destination terminal from the infected terminal and the terminal 50 suspected of being infected. In the example of FIG. 5, the terminal 5 that is connected to the terminal 3 can be infected starting from the terminal 3 that is the infected terminal, and the terminal 5 is identified as a candidate for the infection spread destination terminal and the infection risk score is “0. Add 1 ”. Further, the infection suspect score of the terminal 1 and the terminal 2 is “0.33”, and the terminal 4 that can spread the infection from the terminal 2 is multiplied by “0.1” to “0.33”, and the third decimal point The score “0.03” rounded down is added to the infection risk score.

As a result, as illustrated in FIG. 5, the infection risk score of the terminal 4 is “0.13”. As described above, when the terminal state changes or the infection suspect score or the infection risk score changes, the infection identification unit 12 and the terminal state information stored in the configuration information storage device 30 and the infection Update the suspicion score and infection risk score.

Next, with reference to FIG. 6, description will be given of how to deal with a terminal whose infection is confirmed in the attack countermeasure device 40. FIG. 6 is a diagram for explaining how to deal with a terminal whose infection is confirmed in the attack countermeasure apparatus according to the first embodiment. The attack countermeasure device 40 determines a countermeasure for the terminal 3 when the infection suspect score of the terminal 3 exceeds a first threshold (for example, “0.9”). As illustrated in FIG. 6, since the suspected infection score of the terminal 3 is “1.0” and exceeds the first threshold value, it is determined to deal with the terminal 3. In the example of FIG. 6, since the terminal 3 is a terminal for which infection has been confirmed, as the content of the countermeasure, the terminal 3 is isolated and communication related to the terminal 3 is blocked.

Next, the processing of the specific device 10 and the attack countermeasure device 40 when the security device 20 detects an attack from the terminal 4 to the terminal 5 as a new event will be described with reference to FIGS. FIG. 7 is a diagram for explaining a process for identifying a terminal suspected of being infected and a candidate for an infected terminal in the identifying apparatus according to the first embodiment. FIG. 8 is a diagram for explaining how to deal with a terminal having a high possibility of infection in the attack countermeasure apparatus according to the first embodiment.

As illustrated in FIG. 7, the state specifying unit 11 of the specifying device 10 specifies the states of the terminal 4 and the terminal 5 based on the detection information received from the security device 20 (attack from the terminal 4 to the terminal 5). To do. Here, when an attack from the terminal 4 to the terminal 5 is detected, it can be determined that the terminal 4 has been infected with malware. Therefore, the state of the terminal 4 is identified as an infectious state, and a suspected infection score “1.0” is added to the terminal 4, and the infection suspect score “1.0” of the terminal 4 is set. In the example of FIG. 7, there are two possible routes that can be considered as infection route candidates to the terminal 4, that is, an attack directly made from the Internet 80 via the NW device 60 and an attack via the terminal 2. For this reason, the infection suspicion score to be added from the number “2” of communication paths that can be infection routes is set to “0.5 (1/2)”, and the infection suspicion score of the terminal 2 located on the infection route candidate is “0. 5 ”is added. As a result, the infection suspicion score of the terminal 2 is “0.83”.

Further, since the terminal 5 is under attack from the terminal 4 to the terminal 5, the state of the terminal 5 is identified as the attacked state, and here, "0.5" is added to the infection suspect score, and the infection risk Add “1.0” to the score. As a result, the infection suspicion score of the terminal 5 is “0.5”, and the infection risk score is “1.1”.

Then, as illustrated in FIG. 8, when the suspected infection score exceeds the second threshold (for example, “0.7”), the attack countermeasure device 40 performs communication monitoring and communication as a countermeasure for the terminal 2. Determine limits. As illustrated in FIG. 8, since the suspected infection score of the terminal 2 is “0.83” and exceeds the second threshold value, it is determined to deal with the terminal 2. In the example of FIG. 8, since the terminal 2 is a terminal that has a high possibility of being infected, the contents of countermeasures include communication monitoring and countermeasures for communication restriction. In this way, by performing communication monitoring and communication restriction on a terminal that is highly likely to be infected, the spread of infection to a new terminal 50 when the terminal 2 is infected, and from the terminal 2 External C & C communication connection and the like can be prevented.

Thus, in the specific system 1, every time the security device 20 detects an attack, as described above, the specific device 10 performs a process of specifying a terminal that is suspected of being infected or a terminal that is likely to be infected in the future. By repeating the process, the candidate of the suspected infection terminal is identified, and the infected terminal other than the detected terminal is identified and calculated by, for example, accumulating the number of times the candidate terminal has become a candidate and the information quantifying the suspected infection. In case of infection, it is possible to expand the invasion and reduce the occurrence of damage.

[Process flow of specific device]
Next, the flow of processing of the specifying device 10 according to the first embodiment will be described with reference to FIG. FIG. 9 is a flowchart showing the flow of processing of the specific apparatus according to the first embodiment.

As illustrated in FIG. 9, when the state specifying unit 11 of the specifying device 10 receives the detection information from the security device 20 (Yes in Step S101), the state specifying unit 11 determines the information from the information on the terminal 50 and the activity content of the terminal included in the detection information. The state of the terminal 50 is specified (step S102).

Then, the infection specifying unit 12 of the specifying device 10 refers to the connection information stored in the configuration information storage device 30 when the state specifying unit 11 specifies that the state of the terminal 50 is infected with malware. Then, it is determined whether there is a terminal connected to the infected terminal (step S103).

As a result, if the infection identification unit 12 of the identification device 10 determines that there is no terminal connected to the infected terminal (No at Step S103), the infection identification unit 12 updates the state information of the terminal in the configuration information storage device 30. (Step S105), the process ends.

In addition, when the infection identification unit 12 of the identification device 10 determines that there is a terminal connected to the infected terminal (Yes in step S103), each terminal 50 connected to the infected terminal reaches the infected terminal. The terminal 50 on the route is identified as the suspected infection terminal, and the terminal located ahead of the infected terminal is identified as the infection candidate terminal (step S104). The state information of the terminal of the configuration information storage device 30 is updated (step S105), and the process ends.

[Processing flow of specific system]
Next, the flow of processing of the identification system 1 according to the first embodiment will be described with reference to FIG. FIG. 10 is a sequence diagram showing a flow of processing of the specific system according to the first embodiment.

As shown in FIG. 10, when the security device 20 detects unauthorized communication or the like (step S201), the security device 20 transmits detection information to the specific device 10 (step S202). When receiving the detection information, the specifying device 10 specifies the state of the terminal 50 using the detection information (step S203). Specifically, the specifying device 10 specifies the state of the terminal 50 from the information of the terminal 50 included in the detection information and the activity content of the terminal.

And the specific apparatus 10 requests | requires the connection information memorize | stored in the structure information storage device 30, when it specifies that the state of the terminal 50 is the state infected with the malware (step S204). Subsequently, the identifying device 10 refers to the requested connection information (step S205), and for each terminal 50 connected to the infected terminal, identifies the terminal 50 on the path leading to the infected terminal as a suspected terminal, A terminal located ahead of the infected terminal is identified as an infection candidate terminal (step S206). Thereafter, the identification device 10 updates the state information of the terminal in the configuration information storage device 30 (step S207) and ends the process.

[Effect of the first embodiment]
As described above, the specific device 10 according to the first embodiment receives the detection information from the security device 20 that detects the activity related to the unauthorized intrusion into the network or the infection of the terminal 50, and the terminal included in the detection information The state of the terminal 50 is specified from the information of 50 and the activity content of the terminal 50. Then, when the state specifying unit 11 specifies that the state of the terminal 50 is infected with malware, the specifying device 10 uses the connection information stored in the configuration information storage device 30 as detection information. The terminal 50 that is suspected of being infected before reaching the activity content of the included terminal 50 is identified, and the infected terminal 50 infects the terminal 50 that is located on a route that may be used for unauthorized intrusion or terminal infection in the future. Identify potential infected terminal candidates. For this reason, it is possible not only to detect an infected terminal, but also to identify a terminal that is suspected of being infected or an infected terminal that may be infected in the future.

That is, for example, when the specific device 10 detects an event related to a target-type attack or an APT attack, the specific device 10 is not only a detected terminal, but also a candidate for a terminal that is a route to the detected terminal or an intrusion / infection destination terminal It is possible to identify such terminals, and it is possible to take measures such as strengthening monitoring of these terminals, restricting communication, and blocking communication.

[System configuration, etc.]
Further, each component of each illustrated apparatus is functionally conceptual, and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. For example, regarding the functions of the state specifying unit 11 and the infection specifying unit 12 of the specifying device 10, different devices may have the respective functions. Further, for example, the specific device 10 may store information in the configuration information storage device 30 or may have the function of the attack countermeasure device 40. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

In addition, among the processes described in the present embodiment, all or part of the processes described as being automatically performed can be manually performed, or the processes described as being manually performed can be performed. All or a part can be automatically performed by a known method. In addition, the processing procedure, control procedure, specific name, and information including various data and parameters shown in the above-described document and drawings can be arbitrarily changed unless otherwise specified.

[program]
Further, as one embodiment, the specifying device 10 can be implemented by installing a specific program for executing the above specific processing as package software or online software on a desired computer. For example, the information processing apparatus can be caused to function as the specific apparatus 10 by causing the information processing apparatus to execute the above specific program. The information processing apparatus referred to here includes, for example, a desktop or notebook personal computer. In addition, a terminal device used by a user can be used as a client, and the client can be implemented as a server device that provides services related to the specific processing to the client. For example, the identification device 10 is implemented as a server device that not only detects an infected terminal, but also provides a processing service that identifies a terminal that is suspected of being infected or a candidate for an infected terminal that may be infected in the future. In this case, the specific device 10 may be implemented as a Web server, or may be implemented as a cloud that provides a service related to the above specific processing by outsourcing.

FIG. 11 is a diagram illustrating a computer that executes a specific program. The computer 1000 includes, for example, a memory 1010 and a CPU (Central Processing Unit) 1020. The computer 1000 also includes a hard disk drive interface 1030, a disk drive interface 1040, a serial port interface 1050, a video adapter 1060, and a network interface 1070. These units are connected by a bus 1080.

The memory 1010 includes a ROM (Read Only Memory) 1011 and a RAM (Random Access Memory) 1012. The ROM 1011 stores a boot program such as BIOS (Basic Input Output System). The hard disk drive interface 1030 is connected to the hard disk drive 1031. The disk drive interface 1040 is connected to the disk drive 1041. For example, a removable storage medium such as a magnetic disk or an optical disk is inserted into the disk drive 1041. The serial port interface 1050 is connected to a mouse 1051 and a keyboard 1052, for example. The video adapter 1060 is connected to the display 1061, for example.

The hard disk drive 1031 stores, for example, an OS 1091, an application program 1092, a program module 1093, and program data 1094. That is, a program that defines each process of the specific device 10 is implemented as a program module 1093 in which a code executable by a computer is described. The program module 1093 is stored in the hard disk drive 1031, for example. For example, a program module 1093 for executing processing similar to the functional configuration in the specific device 10 is stored in the hard disk drive 1031. The hard disk drive 1031 may be replaced by an SSD (Solid State Drive).

Further, the setting data used in the processing of the above-described embodiment is stored as program data 1094 in, for example, the memory 1010 or the hard disk drive 1031. Then, the CPU 1020 reads the program module 1093 and the program data 1094 stored in the memory 1010 and the hard disk drive 1031 to the RAM 1012 as necessary, and executes them.

The program module 1093 and the program data 1094 are not limited to being stored in the hard disk drive 1031, but may be stored in, for example, a removable storage medium and read out by the CPU 1020 via the disk drive 1041 or the like. Alternatively, the program module 1093 and the program data 1094 may be stored in another computer connected via a network (LAN (Local Area Network), WAN (Wide Area Network), etc.). Then, the program module 1093 and the program data 1094 may be read by the CPU 1020 from another computer via the network interface 1070.

DESCRIPTION OF SYMBOLS 1 Specific system 10 Specific apparatus 11 State specific part 12 Infection specific part 20 Security apparatus 30 Configuration information storage apparatus 40 Attack countermeasure apparatus 50, 50A-50E Terminal 60 NW apparatus 70 Mail server 80 Internet

Claims (9)

A specific system having a configuration information storage device for storing information related to a terminal in a network and a specific device for specifying a state of the terminal;
The configuration information storage device stores connection information indicating a connection relationship between terminals in the network,
The specific device is:
State identification that receives detection information from a security device that detects activities related to unauthorized intrusion into the network or terminal infection, and identifies the state of the terminal from the information on the terminal included in the detection information and the activity content of the terminal And
If the state specifying unit specifies that the state of the terminal is infected with malware, based on the connection information stored by the configuration information storage device, the activity content of the terminal included in the detection information Identifying a terminal that is suspected of being infected until it reaches the point of infection, and identifying an infected terminal candidate that may infect a terminal that is located on a route that the infected terminal may use in the future for unauthorized intrusion or terminal infection An identification system characterized by having an infection identification unit. When the detection information is information related to communication, the state specifying unit specifies the state of the terminal corresponding to the transmission source address and the transmission destination address of the communication, and when the detection information is information related to the terminal 2. The identification system according to claim 1, wherein the state of the terminal is identified. The configuration information storage device includes address information of terminals in the network, terminal status information indicating a status of the terminal specified by the status specifying unit, a suspected infection specified by the infection specifying unit, and an infected terminal The specific system according to claim 1, wherein candidates are stored. The infection identification unit identifies a terminal included in a communication path that can be an infection route of the infected terminal identified by the state identification unit as a terminal that is suspected of being infected, the number of communication routes that can be the infection route, and the past The identification system according to claim 1 or 2, wherein a numerical value indicating the degree of suspicion of infection is calculated for each terminal suspected of being infected based on the state of the terminal. The infection identification unit starts with the infected terminal identified by the state identification unit, and uses the connection information to identify infected terminal candidates that may infect terminals that can be infected from the infected terminal. 3. The specifying system according to claim 1, wherein the specifying system is specified. The specific system further includes an attack countermeasure device,
The attack handling apparatus blocks communication with an infected terminal identified by the state identifying unit and a terminal with a high suspicion of infection among terminals suspected of being identified identified by the infection identifying unit. The specific system according to claim 1, wherein monitoring or communication restriction is performed. The attack coping apparatus blocks communication of the terminal when the infection suspicion score indicating the degree of suspicion of infection of the terminal exceeds the first threshold, and when the terminal exceeds the second threshold, 7. The specific system according to claim 6, wherein communication monitoring and communication restriction are performed. Detection information about detection is received from a security device that detects activities related to unauthorized intrusion into a network including a plurality of terminals or terminal infection, and the terminal information and the activity contents of the terminal included in the detection information A state identifying unit for identifying a state;
When the state specifying unit specifies that the state of the terminal is infected with malware, the activity of the terminal included in the detection information based on connection information indicating a connection relationship between terminals in the network Identify the terminal that is suspected of being infected up to the contents, and the infected terminal candidate that may infect the terminal located on the route that may be used for unauthorized intrusion or terminal infection in the future An identification device comprising: an infection identification unit for identification. A specific method performed by a specific device,
Detection information about detection is received from a security device that detects activities related to unauthorized intrusion into a network including a plurality of terminals or terminal infection, and the terminal information and the activity contents of the terminal included in the detection information A state identification step for identifying a state;
In the case where the state of the terminal is identified as being infected with malware by the state identification step, the activity of the terminal included in the detection information based on connection information indicating a connection relationship between terminals in the network Identify the terminal that is suspected of being infected up to the contents, and the infected terminal candidate that may infect the terminal located on the route that may be used for unauthorized intrusion or terminal infection in the future An identification method characterized by including an infection identification step to identify.

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